Genetically engineered yeasts could make it easy to produce opiates such as morphine anywhere, cutting out the international traffickers and making such drugs cheap and more readily available. If home-brew drugs become widespread, it would make the Sisyphean nature of stopping the supply of illegal narcotics even more obvious than it is now.

“It would be as disruptive to drug enforcement policy as it would be to crime syndicates,” says Tania Bubela, a public health researcher at the University of Alberta in Edmonton, Canada. “It may force the US to rethink its war on drugs.”

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A growing number of drugs, scents and flavours once obtainable only from plants can now be made using genetically modified organisms. Researchers want to add opiates to that list because they are part of a family of molecules that may have useful medicinal properties (see “The yeast route to new painkillers“). Plant yields of many of these molecules are vanishingly small, and the chemicals are difficult and expensive to make in the lab. Getting yeast to pump them out would be far cheaper.

Yeasts capable of doing this do not exist yet, but all the researchers that New Scientist spoke to had no doubt that they soon will. “The field is moving much faster than we had previous realised,” says John Dueber of the University of California, Berkeley, whose team has just created a yeast that makes the main precursor chemical needed to produce opiates. Until recently, Dueber had thought that the creation of, say, a morphine-making yeast was 10 years away. He now thinks a low-yielding strain could be made in two or three years.

It might take many more years to produce a high-yielding strain. But once it exists, in theory anyone who got hold of it could make morphine in their kitchen using a home-brewing kit. Drinking tiny quantities of the resulting brew – perhaps as little as a few millilitres – would get you high. “It probably is as simple as that,” says Dueber. “The beer would have morphine in it.”

In theory, anyone who has the yeast could make morphine in their kitchen using a home-brewing kit

We need to start thinking about the implications now, before such strains – or the recipes for genetically engineering them – become available, he says.

Other teams are working on producing tropane alkaloids – a family of compounds that include drugs such as cocaine. Cocaine-making yeasts are further off, as we still don’t understand certain critical steps that coca plants use to make the stuff.

But there’s no reason we cannot engineer yeast to produce any substance that plants produce, once we understand the machinery, says biochemist Peter Facchini of the University of Calgary in Canada. “So indeed, someone could potentially produce cocaine in yeast,” he says.

If these kinds of biosynthetic yeasts became widely available, they could transform the supply of illicit drugs. Instead of substances like heroin and cocaine being grown abroad and imported by criminal gangs, they could be produced locally by individuals or small groups. It would “democratise” production, as Dueber puts it.

Brewing would also be much harder to detect or prevent than the cultivation of drug-yielding plants. Growing cannabis indoors, for instance, requires a lot of electricity to power lights. A drug-producing “microbrewery” would have only a tiny footprint.

Synthesising drugs like methamphetamines in small illegal labs, meanwhile, requires not only expertise but also the right chemical ingredients. Cutting off the supply of these chemicals is one of the main strategies of law enforcement efforts. This would be impossible with home-brew drugs – the only raw material needed is sugar.

Cutting off the raw materials for drug-making is impossible with home brew – it just needs sugar

And unlike crystal meth production, brewing does not create a toxic mess&colon; the waste products are just brackish water and some very mild chemicals such as acetate, says Dueber.

In a commentary in Nature, Bubela and her co-authors say governments need to act now if they want to prevent morphine-making yeasts getting into the wrong hands (doi.org/4q9). Some fear that drug use could soar if home-brewing makes drugs easily available.

But it is far from clear that this is a likely scenario, especially for rich countries such as the UK. Here the war on drugs has already failed&colon; opiates like heroin are sold very cheaply on the street, says David Nutt of Imperial College London, a former drug policy adviser to the UK government. “People don’t take them because most of them are not stupid.”

In theory, home-brew drugs could deprive traffickers in countries such as Afghanistan and Colombia of their main source of revenue – money that fuels corruption and other criminal activities, destabilises governments and even funds terrorism. “If I were a member of a criminal syndicate, I would not like this very much,” says Kenneth Oye, a political scientist at the Massachusetts Institute of Technology, and one of Bubela’s co-authors.

Bringing heroin home

But it is hard to say how things would pan out. “You’d be battling the illicit market with another illicit, home-grown market,” says Dueber. “Is that a good solution? I don’t know.”

Until last year, for instance, coca cultivation in Colombia had been declining. But the criminal gangs didn’t vanish; instead, they turned to illegal mining and logging, says Liliana Davalos of Stony Brook University in New York, who has studied the environmental impacts of coca growing. “The traffickers have shifted their portfolio,” she says. It’s not clear if they are even any poorer.

All this assumes that bioengineered yeast capable of making drugs does become widely available. There are two ways for that to happen&colon; a yeast strain engineered for the purpose could be stolen from a laboratory or legal factory, or someone could independently genetically engineer ordinary yeast to do it.

Oye and Bubela say four kinds of measures are needed. Distributing opiate-making yeast strains should be made illegal. The strains themselves should be altered to make them hard to grow outside specialised facilities, for instance by making them dependent on unusual nutrients. The strains should also be kept in secure, government-licensed facilities. And companies that sell custom DNA sequences should refuse to supply the genes needed to engineer such strains.

If the history of drug control efforts is anything to go by, though, such measures won’t prevent the cat from being let out of the bag before too long.

The Yeast route to new painkillers

The world’s supply of legal opiates comes from poppy fields in Australia, Turkey and India. If we manage to create opiate-producing yeast, the ultimate aim will not be to replace opium poppies but to make innovative forms of these drugs.

There is a real need for safer painkillers, says Kenneth Oye at the Massachusetts Institute of Technology, such as less addictive opiates and ones that don’t cause occasional breathing problems.

What’s more, opiates are part of a much bigger family of around 2500 molecules, many of which are thought to have anticancer or antibiotic properties, says John Dueber of the University of California, Berkeley. Getting yeasts to pump out these kinds of molecules cheaply would make it much easier to explore their potential.

By adding the genes for the plant enzymes involved in the first part of the chemical pathway, Dueber’s group has created yeast that produces S-reticuline, the main precursor of all 2500 molecules (Nature Chemical Biology, doi.org/4q8). The next step is to add genes for the enzymes involved in the pathway from S-reticuline to molecules such as morphine. It will also be possible to create related molecules that do not exist in nature, including novel opiates.

Three other groups have worked out the beginning, middle and end stages of the process needed to produce opiates from S-reticuline. In theory, combining their work could create an opiate-producing yeast tomorrow. In practice, it is likely to take years to iron out all the wrinkles.

This article appeared in print under the headline “Just a sip could get you high”